Process for making curved flanged bars



R. 3. SMITH. PROCESS FOR MAKING CURVED FLANGED BARS.

APPLICATION FILED APR. 15,1920.

. Patented Oct. 26,1920.

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WITNESS I j 5%, I I I .arrazms'r UNITED S'TATES PATENT oer-Ice.

REUBEN STANLEY SMITH, OF MILWAUKEE, WISCONSIN.

PROCESS FOR MAKING CURVED FLANGED BARS;

Application filed April 15,

To all whom it may concern:

Be it known that I, REUBEN STANLEY SMITH, a citizen of the United States, residing in the city of Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Processes for Making Curved Flanged Bars, (Case #154;) and do hereby declare the following to be a full, clear, and exact description thereof, such .as will enable persons skilled in the .art to which the invention pertains to use the same, reference being bad to the drawings hereto attached for disclosure as to certain details of the manner in which the invention is reduced to practice.

My invention relates to improvements in processes of shaping sheet metal -blankrs,. particular reference being made to that class of operations in which the side mar- Y gins of a curved blank are bent so as to" stand in parallel planes which are normal to the plane of the central portion or web'of the blank, to form a channel bar. The invention is primarily designed for use in the production of side bars and cross bars of automobile or other vehicle frames. While I have chosen to illustrate and describe my invention as applicable to the production of a cross bar blank for an automobile frame, it will beunderstood that this particular application has been selected as a mere conventional exposition of the invention, and that the latter is not to be limited in its application to the production of such cross bars, but may also be applied to the production of side bars of automobile frames, as well as to the production of curved channel bars intended for other uses.

The invention herein disclosed embodies in its broader aspects the process for making curved flanged bars covered by my application, Serial No. 288,085,filed April 5,1919, since then matured into Patent #1,348,647, dated June 15, 1920, to which reference may behad for disclosure of the invention in some of the'more specific forms of its application.

The present invention is applicable in particular to flat sheet metal blanks of curved outline, but the manner of producing 'such curved blanks is not material to the purposes of my said invention. Asa matter of fact, such curved blanks may be punched from wide rectangular plates, or they may be punched from comparatively Specification of Letters Patent.

Patented Oct. 26, 1920. 1920. Seria1 No.3 74,174.

narrow rectangular plates, which have been bent edgewise or in the direction of their width. The first mentioned method of producmg curved blanks from wide rectangular plates is very wasteful, and I prefer, as

a matter of economy, to resort to the more modern method of bending a comparatively narrow rectangular plate edgewise', so as to present an irregular area from which the curved blank to form the channel bar may be punched, without the waste incident tothe former methods.

. The curved blanks produced by either of i the practices outlined above, are fed to a drawing press of usual type, the dies of whlch act to turn the side margins from flanges of the bar-is contracted, with the result that each of such marginal sections Con versely, the length of the marginal sections is thickened throughout its extent.

forming the concave portions is expanded longitudinally, with the result that such portion is unduly stretched, thereby produc ing a weakness and sometimes te'arlngthe blank byreason of an uneven molecular displacement of the material of which the blank is formed. I i

It is the purpose of my present invention to crimp or corrugate the side margins of the curved blankat the points where the concave flanges are to be formed, so that the molecular displacement occurring in the concave margin when the latter is turned will be evenly distributed throughout the length thereof, and will present a surplus of material which will compensate the expansion which takes place in the drawing operation.

material in theportionsof the flanges which are concaved, will permit such flanges to be turned to their perpendicular positions with reference to the plane of the blank, 'without exerting a tearing strain at-any point. Thus, when the concave margins 'of" the curved blank are subjected to the drawing operation, the material at those points will stretch evenly throughout the crimped or corrugated area, so that structural weakness in the channel bar is avoided.

In the drawing operation, the lateral This provision of additional pressure'exerted upon the corrugated mar.

sectional view at any given point, of the structure as shown in Fig. 1, this view showing also in dotted lines the side margins of the blank as lying in the plane of the blank, from which they are turned in the drawing operation to form the flanges of the bar.

Fig. 3 is a plan view of a curved blank, from which the cross bar of F igs. 1 and 2 is formed, this view illustrating my method of crimping the margins of the blank at those portions where the concave flanges are to be formed. r

Fig. 4% is a View in elevation showing a portion of the concave edge of the blank, and looking in the direction of the arrow 4 in Fig. 3.

i Fig. 5 is a cross section on the line 5-5, Fig. 3, the line cutting the concave margins at opposite sides of the blank and showing the displacement caused by crimping.

Fig. 6 is a cross section on the line 6-6,

Fig. 3.

Referring to the drawings, Fig. 1 illustrates in perspective a conventional cross bar 1, composed of a vertical web 2 and top and bottom flanges 3 and 4, respectively. The top flange comprises plain end portions 5, convex portion 6 and a plurality of concave portions 7. The bottom flange 4, parallel through its length with the flange 3, is composed of plain end portions corresponding to the portions 5 of the top flange, a concave portion 8 and a plurality of convex portions 9. The curved blank 10, Fig. 3, is adapted. to have its margins 11 and 12 folded along the dotted lines 11 and 12 ,so as to form the reinforcing flanges of the channel bar.

The areas indicated, 7 7 and 8 in Fig. 3 form the concave portions 7, 7, and 8, respectively, of the completed cross bar. The areas 7 7 and 8 are crimpedor corrugated by the action of suitable (lies in a stamping press. so that the effect of the operation of the press is to transform the concave margins of the curved blank from the flat plane of the blank into corrugated surfaces, such as is indicated in Fig. 4.

In connection with the concave edge 80f the cross bar, I have indicated in Fig. 3 the extent of the molecular displacement which Occurs when the margin of the blank forming such concave edge is turned intoa plane which is normal with respect to the plane of the blank. The dotted line 13 in Fig. 3 indicates the normal length of the concave edge of the curved blank, and the dotted line 14 in the same figure indicates the length of the edge of the concave flange after it has been turned from the plane of the blank.

By means of this comparison, 1t will be seen that the metal of the concave margin 111 being turned, must be expanded in a considerable degree, and that unless the strain is evenly distributed over the whole of the area, the material is apt to' tear at its weakest point, or at least be so strained as to be liable to fracture.

The dies of the press which crimp the margins of the curved blank at the points where the concaveflanges are to be formed, may draw upon the material at each end of the concave portion, and impart a fullness which increases slightly the linear measurement of the concave part. The surplus material thus. created enables the concave flange to be turned without undue strain at any point, so that the integrity of the flanged bar is preserved and the weakness insepara ble from the older methods of production is completely eliminated.

The punch of the drawing press will have a width equal to the distance between the dotted parallel curved lines 11 and 12 Fig. 3. The curved blank is laid over the matrix, and-when the punch is actuated to press the blank into the matrix, the margins lying beyond the said dotted lines 11 and 12 will be-folded against the opposite sides of the punch, as the latter is forced into the matrix. The lateral pressure exerted simultaneously by the side walls of the matrix upon the flanges and against the punch, will smooth out the crimps or corrugations as the punch and the blank enter the matrix. In some constructions of drawing presses, the side members of the matrix are capable of joint movement toward-each other, to impart a set to the flanges of the bar as the punch completes the drawing operation. In presses of this type, such movement of the! side members of the matrix, with the'resultant lateral pressure, may be utilized to press-i.

out the crimps or corrugations in the concave flanges.

In the drawing operation, the convex portions of the margins will be shortened by reason of their being crowded into an arc of less length, and thus the material at these points will be slightly thickened. At the same time these convex portions will tend to elongate, and thus augment the concave portions by the addition of material which will be absorbed in the crimped or corrugated sections out of which the concave flanges are formed.

Having thus described my invention, what I claim to secure by Letters Patent of the United States is:

1. The process of forming curved flanged bars from sheet metal plates, which consists in crimping the margins of a curved plate at points so as to provide a fullness to avoid stretching of the metal in producing the concave flanges, bending the side margins away from the plane of the plate to form the flanges of the bar, and eliminating the crimps by pressure upon the curved flanges.

2. The process of forming fiat metal plates of curved outline into curved flanged bars, which consists in crimping the margins of the plate at the concaved portions to provide a fullness to avoid stretching the metal in producing the concave flanges, bending the side margins away from the plane of the plate to form the flanges of the bar, andeliminating the crimps by pressure.

3. The process of forming flat metal,

plates of curved outline into curved flanged bars, which consists in crimping the margins of the plate at the concaved portions to provide a fullness to avoid stretching the metal anges of the bar and eliminating the crimps by pressure applied during the flange bending operation.

4. The process of forming flat metal plates of curvedoutline of the plate at the concaved portions to pro vide a fullness to avoid stretching-the metal in producing the concave flanges, turnin the side margins away from the plane of the plate and into parallel planes standing normal to the plane of the plate to form the flanges, and simultaneously eliminating the crimps in both flanges by lateral pressure.

In testimony whereof, I have signed my name at Milwaukee, this 13th day of 1920.

R. STANLEY SMITH.

into curved flanged bars,'whlch consists 1n crimping the margms.

April, 

